aerodynamicists, regularly participate in the development of our motorsport projects.
Michal Sumec (Aerodynamicist Škoda Auto, Czech Republic) will report the aerodynamic development of the Škoda Fabia R5 Rally Car and its benefits to the series development.
The R5 class applies to 1600cc turbocharged petrol 4WD series production cars. With the FIA imposing a ‘price cap’ on all major parts (or example, a complete turbocharger will cost 1000 euros, a front subframe 2500 euros and an R5 bodyshell complete with homologated safety cage for a very reasonable 18,500 euros), there has been an increase emphasis on aerodynamic efficiency.
“In order to support a market launch of the new generation of Fabia, the Rally version (in R5 FIA-Class) was developed at the same time during the development of the series car” says Sumec.
“Special aspects of a typical use of a rally car to the aerodynamics (road: tarmac / gravel / snow or ice, average speed ranging from 60 kph to 120 kph, temperature range from -20°C to +50°C and altitude ranging from 0m to 2500m asl) ”.
Sumec will also details Skoda’s project goals, tasks and disciplines, as well as aerodynamic efficiency, drag, down-force
and approaches to cooling in various competition environments.
A direct competitor to the Skoda - the 2015 Mitsubishi Mirage R5 - has been designed designed to function as a package to enhance the overall dynamics of the car by maximizing down force that presses the tyres against the pavement for optimal grip and control.
Last year 2014, the rear fascia on the Mirage had been redesigned with sculptural decklid and diffuser to produce low pressure. A hood air extractor also contributes to improved cooling and aerodynamic efficiency.
Mitsubishi Mirage R5 in testing
Thermal and Aerodynamic Development for New NSX-New Honda FIT/JAZZ/Accord
Unlike rallying and circuit racing, aerodynamicists for road-going sports cars face a unique set of challenges. Balancing performance on the open road, in traffic must all be considered whilst maintaining a harmonious and striking aesthetic that attracts a sports car enthusiast.
Yasuyuki Onishi (Assistant Chief Engineer Honda R&D Co., Ltd, Japan) will be on hand to discuss the challenges that aerodynamicists face in the design of a sports car.
“A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed and acceleration time, lift - or down force - and balance that affects handling and stability, cooling that insures the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and aesthetic” explains Onishi-San.
Like Honda, Toyota too has understood the subtle balance between aesthetics and road-going performance, prompting a rethink in their own aero design parameters in coming up with the 'Sandwhich Concept for the Toyota 86.
Airflow creates a 'sandwich' of air above, below and to the sides of the car. This envelope of air stabilises the car and prevents unnecessary down-force, helping to ensure that every drop of fuel contributes to performance.
With a drag coefficient of just 0.27, the 86 is designed to slip through the air with minimum resistance. Furthermore, the 86's curved hood and pagoda roof act to reduce the car's frontal projection area with every detail of the car's surface and underbody, shaped to contribute to the aerodynamics.
In addition, the lower grille area has been shaped so that airflow is directed at the front brake calipers helping to disperse heat from braking.
Cooling was also a major consideration at Honda, as Onishi-San explains further:
“Our NEW NSX for example applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, so additional cooling was required”.
Yasuyuki Onishi’s presentation will focus on the cooling and heat resistance concept based on the overall airflow structure concept around the NSX as well as the new Honda FIT/JAZZ/Accord Hybrid.
“During the prior study, phenomenon analyses were conducted to identify areas that have a significant effect on aerodynamics and the package design by using a 25% scale model” says Onishi-San. Computational fluid dynamics (CFD) also played a big role to understand the phenomena. Both model aerodynamics developments were focused on controling the pressure balance to reduce total pressure loss region and the longitudinal vortex drag behind the vehicle.”
Yasuyuki Onishi, Michal Sumec, Christian Taucher and Franck Sanchez will all be presenting at the Advanced Automotive Aerodynamics International Forum on the 9th and 10th of June in Nantwich, UK.
For tickets go to http://www.internect.co.uk/content/91/international-forum-advanced-automotive-aerodynamics or email [email protected]
Yasuyuki Onishi, Assistant Chief Engineer Honda R&D Co., Ltd, Japan.
Additional material courtesy Matt Layton /HighPower media